I think #3 is best as well. Ok, so I played around a bit with making a transparent png. The shadows are also included in the png. Here's a few examples with different backgrounds that I changed in Photoshop. The result will not be as realistic as a real render since for example the surrounding color will not be reflected on the joystick, but I think it looks pretty ok. The last one is the transparent png that you could try out yourself.

I like the shadow!
You can easily Magic Wand the background and only get the Tomahawk to put in every picture you'd like... but anywayz, in this image putting Tomahawk flipped due to the angle and cable... is bad! Inverted logo and button is failz0rz

No it's not fully transparent because it receives some subtle shadows. I can probably get rid of it if I move lights and object around on trial and error, but that's too much work. I could get rid of all the shadows if you want though.

Ok, finished the final touches. So this is the final image. The background is now completely transparent except the shadows under the joystick and cord. So what resolution is enough? Obviously it takes longer the render higher resolutions.upload pngpng

Ok, so here's the final image, 3360x2100 transparent png. There is a slight dark outline that I think looks crap, but oh well, a lot of things to hae in mind when dealing with transparency. I think it looks ok though. Click the image to get the png.